X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/db518d9b6f0e149631deb137bb00841f93b0d6d8..6a2c4cd8b3908e0d7e28789e83b4dc2b69aaf6d4:/canohost.c diff --git a/canohost.c b/canohost.c index 03005aa2..057f061b 100644 --- a/canohost.c +++ b/canohost.c @@ -12,7 +12,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: canohost.c,v 1.31 2002/02/27 21:23:13 stevesk Exp $"); +RCSID("$OpenBSD: canohost.c,v 1.40 2004/06/21 17:36:31 avsm Exp $"); #include "packet.h" #include "xmalloc.h" @@ -20,6 +20,7 @@ RCSID("$OpenBSD: canohost.c,v 1.31 2002/02/27 21:23:13 stevesk Exp $"); #include "canohost.h" static void check_ip_options(int, char *); +static void ipv64_normalise_mapped(struct sockaddr_storage *, socklen_t *); /* * Return the canonical name of the host at the other end of the socket. The @@ -27,7 +28,7 @@ static void check_ip_options(int, char *); */ static char * -get_remote_hostname(int socket, int verify_reverse_mapping) +get_remote_hostname(int sock, int use_dns) { struct sockaddr_storage from; int i; @@ -38,50 +39,49 @@ get_remote_hostname(int socket, int verify_reverse_mapping) /* Get IP address of client. */ fromlen = sizeof(from); memset(&from, 0, sizeof(from)); - if (getpeername(socket, (struct sockaddr *) &from, &fromlen) < 0) { + if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) { debug("getpeername failed: %.100s", strerror(errno)); - fatal_cleanup(); + cleanup_exit(255); } -#ifdef IPV4_IN_IPV6 - if (from.ss_family == AF_INET6) { - struct sockaddr_in6 *from6 = (struct sockaddr_in6 *)&from; - /* Detect IPv4 in IPv6 mapped address and convert it to */ - /* plain (AF_INET) IPv4 address */ - if (IN6_IS_ADDR_V4MAPPED(&from6->sin6_addr)) { - struct sockaddr_in *from4 = (struct sockaddr_in *)&from; - struct in_addr addr; - u_int16_t port; - - memcpy(&addr, ((char *)&from6->sin6_addr) + 12, sizeof(addr)); - port = from6->sin6_port; + if (from.ss_family == AF_INET) + check_ip_options(sock, ntop); - memset(&from, 0, sizeof(from)); + ipv64_normalise_mapped(&from, &fromlen); - from4->sin_family = AF_INET; - memcpy(&from4->sin_addr, &addr, sizeof(addr)); - from4->sin_port = port; - } - } -#endif - if (from.ss_family == AF_INET) - check_ip_options(socket, ntop); + if (from.ss_family == AF_INET6) + fromlen = sizeof(struct sockaddr_in6); if (getnameinfo((struct sockaddr *)&from, fromlen, ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0) fatal("get_remote_hostname: getnameinfo NI_NUMERICHOST failed"); + if (!use_dns) + return xstrdup(ntop); + debug3("Trying to reverse map address %.100s.", ntop); /* Map the IP address to a host name. */ if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), NULL, 0, NI_NAMEREQD) != 0) { /* Host name not found. Use ip address. */ - log("Could not reverse map address %.100s.", ntop); return xstrdup(ntop); } - /* Got host name. */ - name[sizeof(name) - 1] = '\0'; + /* + * if reverse lookup result looks like a numeric hostname, + * someone is trying to trick us by PTR record like following: + * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_socktype = SOCK_DGRAM; /*dummy*/ + hints.ai_flags = AI_NUMERICHOST; + if (getaddrinfo(name, "0", &hints, &ai) == 0) { + logit("Nasty PTR record \"%s\" is set up for %s, ignoring", + name, ntop); + freeaddrinfo(ai); + return xstrdup(ntop); + } + /* * Convert it to all lowercase (which is expected by the rest * of this software). @@ -89,9 +89,6 @@ get_remote_hostname(int socket, int verify_reverse_mapping) for (i = 0; name[i]; i++) if (isupper(name[i])) name[i] = tolower(name[i]); - - if (!verify_reverse_mapping) - return xstrdup(name); /* * Map it back to an IP address and check that the given * address actually is an address of this host. This is @@ -105,7 +102,7 @@ get_remote_hostname(int socket, int verify_reverse_mapping) hints.ai_family = from.ss_family; hints.ai_socktype = SOCK_STREAM; if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { - log("reverse mapping checking getaddrinfo for %.700s " + logit("reverse mapping checking getaddrinfo for %.700s " "failed - POSSIBLE BREAKIN ATTEMPT!", name); return xstrdup(ntop); } @@ -120,7 +117,7 @@ get_remote_hostname(int socket, int verify_reverse_mapping) /* If we reached the end of the list, the address was not there. */ if (!ai) { /* Address not found for the host name. */ - log("Address %.100s maps to %.600s, but this does not " + logit("Address %.100s maps to %.600s, but this does not " "map back to the address - POSSIBLE BREAKIN ATTEMPT!", ntop, name); return xstrdup(ntop); @@ -141,8 +138,9 @@ get_remote_hostname(int socket, int verify_reverse_mapping) */ /* IPv4 only */ static void -check_ip_options(int socket, char *ipaddr) +check_ip_options(int sock, char *ipaddr) { +#ifdef IP_OPTIONS u_char options[200]; char text[sizeof(options) * 3 + 1]; socklen_t option_size; @@ -154,17 +152,43 @@ check_ip_options(int socket, char *ipaddr) else ipproto = IPPROTO_IP; option_size = sizeof(options); - if (getsockopt(socket, ipproto, IP_OPTIONS, options, + if (getsockopt(sock, ipproto, IP_OPTIONS, options, &option_size) >= 0 && option_size != 0) { text[0] = '\0'; for (i = 0; i < option_size; i++) snprintf(text + i*3, sizeof(text) - i*3, " %2.2x", options[i]); - log("Connection from %.100s with IP options:%.800s", + logit("Connection from %.100s with IP options:%.800s", ipaddr, text); packet_disconnect("Connection from %.100s with IP options:%.800s", ipaddr, text); } +#endif /* IP_OPTIONS */ +} + +static void +ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len) +{ + struct sockaddr_in6 *a6 = (struct sockaddr_in6 *)addr; + struct sockaddr_in *a4 = (struct sockaddr_in *)addr; + struct in_addr inaddr; + u_int16_t port; + + if (addr->ss_family != AF_INET6 || + !IN6_IS_ADDR_V4MAPPED(&a6->sin6_addr)) + return; + + debug3("Normalising mapped IPv4 in IPv6 address"); + + memcpy(&inaddr, ((char *)&a6->sin6_addr) + 12, sizeof(inaddr)); + port = a6->sin6_port; + + memset(addr, 0, sizeof(*a4)); + + a4->sin_family = AF_INET; + *len = sizeof(*a4); + memcpy(&a4->sin_addr, &inaddr, sizeof(inaddr)); + a4->sin_port = port; } /* @@ -174,14 +198,14 @@ check_ip_options(int socket, char *ipaddr) */ const char * -get_canonical_hostname(int verify_reverse_mapping) +get_canonical_hostname(int use_dns) { static char *canonical_host_name = NULL; - static int verify_reverse_mapping_done = 0; + static int use_dns_done = 0; /* Check if we have previously retrieved name with same option. */ if (canonical_host_name != NULL) { - if (verify_reverse_mapping_done != verify_reverse_mapping) + if (use_dns_done != use_dns) xfree(canonical_host_name); else return canonical_host_name; @@ -190,20 +214,20 @@ get_canonical_hostname(int verify_reverse_mapping) /* Get the real hostname if socket; otherwise return UNKNOWN. */ if (packet_connection_is_on_socket()) canonical_host_name = get_remote_hostname( - packet_get_connection_in(), verify_reverse_mapping); + packet_get_connection_in(), use_dns); else canonical_host_name = xstrdup("UNKNOWN"); - verify_reverse_mapping_done = verify_reverse_mapping; + use_dns_done = use_dns; return canonical_host_name; } /* - * Returns the remote IP-address of socket as a string. The returned - * string must be freed. + * Returns the local/remote IP-address/hostname of socket as a string. + * The returned string must be freed. */ static char * -get_socket_address(int socket, int remote, int flags) +get_socket_address(int sock, int remote, int flags) { struct sockaddr_storage addr; socklen_t addrlen; @@ -214,45 +238,52 @@ get_socket_address(int socket, int remote, int flags) memset(&addr, 0, sizeof(addr)); if (remote) { - if (getpeername(socket, (struct sockaddr *)&addr, &addrlen) - < 0) { - debug("get_socket_ipaddr: getpeername failed: %.100s", - strerror(errno)); + if (getpeername(sock, (struct sockaddr *)&addr, &addrlen) + < 0) return NULL; - } } else { - if (getsockname(socket, (struct sockaddr *)&addr, &addrlen) - < 0) { - debug("get_socket_ipaddr: getsockname failed: %.100s", - strerror(errno)); + if (getsockname(sock, (struct sockaddr *)&addr, &addrlen) + < 0) return NULL; - } } + + /* Work around Linux IPv6 weirdness */ + if (addr.ss_family == AF_INET6) + addrlen = sizeof(struct sockaddr_in6); + /* Get the address in ascii. */ if (getnameinfo((struct sockaddr *)&addr, addrlen, ntop, sizeof(ntop), NULL, 0, flags) != 0) { - error("get_socket_ipaddr: getnameinfo %d failed", flags); + error("get_socket_address: getnameinfo %d failed", flags); return NULL; } return xstrdup(ntop); } char * -get_peer_ipaddr(int socket) +get_peer_ipaddr(int sock) { - return get_socket_address(socket, 1, NI_NUMERICHOST); + char *p; + + if ((p = get_socket_address(sock, 1, NI_NUMERICHOST)) != NULL) + return p; + return xstrdup("UNKNOWN"); } char * -get_local_ipaddr(int socket) +get_local_ipaddr(int sock) { - return get_socket_address(socket, 0, NI_NUMERICHOST); + char *p; + + if ((p = get_socket_address(sock, 0, NI_NUMERICHOST)) != NULL) + return p; + return xstrdup("UNKNOWN"); } char * -get_local_name(int socket) +get_local_name(int sock) { - return get_socket_address(socket, 0, NI_NAMEREQD); + return get_socket_address(sock, 0, NI_NAMEREQD); } /* @@ -271,7 +302,7 @@ get_remote_ipaddr(void) canonical_host_ip = get_peer_ipaddr(packet_get_connection_in()); if (canonical_host_ip == NULL) - fatal_cleanup(); + cleanup_exit(255); } else { /* If not on socket, return UNKNOWN. */ canonical_host_ip = xstrdup("UNKNOWN"); @@ -281,11 +312,11 @@ get_remote_ipaddr(void) } const char * -get_remote_name_or_ip(u_int utmp_len, int verify_reverse_mapping) +get_remote_name_or_ip(u_int utmp_len, int use_dns) { static const char *remote = ""; if (utmp_len > 0) - remote = get_canonical_hostname(verify_reverse_mapping); + remote = get_canonical_hostname(use_dns); if (utmp_len == 0 || strlen(remote) > utmp_len) remote = get_remote_ipaddr(); return remote; @@ -309,11 +340,16 @@ get_sock_port(int sock, int local) return 0; } } else { - if (getpeername(sock, (struct sockaddr *) & from, &fromlen) < 0) { + if (getpeername(sock, (struct sockaddr *)&from, &fromlen) < 0) { debug("getpeername failed: %.100s", strerror(errno)); - fatal_cleanup(); + cleanup_exit(255); } } + + /* Work around Linux IPv6 weirdness */ + if (from.ss_family == AF_INET6) + fromlen = sizeof(struct sockaddr_in6); + /* Return port number. */ if (getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0, strport, sizeof(strport), NI_NUMERICSERV) != 0)